Primes PROFINET - Execution of the Power Measurement

PowerMeasuringModule PMM
35,0(
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Revision 13 EN - 02/2023
10.2 Execution of the power measurement
The PMM is ready for measurement when the “Ready for Measurement” status bit is set (shutter is open,
temperature is OK).
To initialize the PMM for the measurement the external control system must set the “start” bit in the “Com-
mand” byte (please see Fig. 10.2 on page50).
Command.start
tlaser
twait
X
X
X
valid valid
valid valid
tthermalization
status.acknowledge
Laser On
status.ready (Ready for Measurement)
status.measurement running
status.measurement finished
Measured power
Measured Energy
Fig. 10.2: Timing diagram of the measurement cycle
The PMM answers the starting command with an “acknowledge” in status byte1.
As soon as the PMM is ready for measurement the “ready” bit is set in the status byte1.
Before starting the laser pulse, check that status Byte1 Bit0 is set to 1.
From this point on, the laser can irradiate the absorber using the calculated irradiation time (see chapter8.6
„Calculation of the irradiation time“ on page41.
If the shutter is not in the open position or a laser pulse is detected, the “ready” status is deleted.
After the laser pulse, the PMM can identify the laser pulse due to the temperature rise of the absorber and
the signal from the internal photodiode. The following thermalization period of the absorber is indicated by
the bit “running” in the status byte.
At the end of the thermalization phase (approx. 10 seconds for standard devices and 3 seconds for devices
with reduced thermalization time - PMM type AP3s), the measurement result is calculated and the “measure-
ment finished” bit is set. The results of the measurement can be displayed now.
If the measuring procedure is supposed to be aborted without a measurement and the shutter is
supposed to be closed again, a reset has to be carried out (Do_reset; set bit 7 in the command
byte, see Tab. 11.2 on page54 ).